After seeing your temps, your basking spot is too low. It should be around 130 degrees. When a herp seems "tired" it usually means it has been kept at too low of temperatures. Sometimes petstores use this to make their animals seem "tame" or "friendly" when actually they are just too cold.
Another thing is the food. Offer feeder insects. Dubia roaches are usually the best and most preffered by herp keepers. Id suggest getting a colony established now.
Also how are you achieving the basking spot? With a plastic tub, reaching 130to 140 degrees with a lamp can be really sketchy seeing as how plastic melts.
For some basic care, Id suggest going here.
http://www.proexotics.com/care_savannah.html
Pro exotics is one of the best companies to deal with and has some of the best herps in the hobby.
Goodluck with your sav. Im hoping he does well. Many of the monitors brought into this hobby die very early on.